This program of research is concerned with the effects of hypnosis and self-hypnosis on clinically relevant psychobiologic processes. Five projects concern the effects of hypnosis on emotional, behavioral, psychoimmunological, and sleep responses to stress and pain. Project 1 seeks to document that hypnosis can alter the effects of a specific life stressor on psychological distress and immune function. Projects 2A and 2B prospectively study the effects of self-hypnosis for controlling unpredictable acute pain due to vaso-occlusive crises in children and adults who suffer from sickle cell disease. Project 3 addresses the role of hypnosis in the treatment of pain in patients with fibromyalgia syndrome, and the relationship of fibromyalgia with abnormal sleep patterns and immune function. Sleep disturbance is a common feature of response to stress and sleep is often associated with recovery from illness. Project 4 focuses on the link between sleep, sleep loss and immune function. The second major focus is on the relationship of hypnosis to dissociative aspects of sleep. Project 5 evaluates whether hypnosis can be used to create physiological sleepiness in an effort to shed light on "pathological" sleepiness. Projects 6A and 6B investigate the relationship between dissociative aspects of hypnosis and dissociative aspects of sleep (parasomnias). 6A examines the role of psychopathology, while 6B explores parasomnias and hypnotizability in healthy children and adults. Projects 7 and 8 study specific dissociative features of parasomnias. The overall coordination of the program is managed through five cores (hypnosis, sleep, and immune assessments, data analyses, administration). The clinically relevant phenomena on which the program focuses necessarily require a multidisciplinary team of active collaborators, including psychologists, psychiatrists, immunologists, rheumatologists, hematologists, and sleep psychophysiologists. The overall aim is to study the effect of cognitive processes on psychobiologic systems that are relevant to physical and mental health.